Basically they must be installed in enclosures, cabinets, cutout boxes, or equipment assemblies.
There are other considerations also.
Can you be a little more specific?
This was a long length of wireway with receptacles installed in it every couple of feet. Next to each recept was a circuit breaker. These were also installed inside the wireway, with the handles outside and accessible.
I had never seen this before and was wondering if wireways might be listed for this application.